The elder sister of your mother is called your "aunt." Specifically, she is your maternal aunt. In some cultures, she may also be referred to using terms that denote affection or respect.
just call her by her first name, she is no relation to you.
He will be called ' massi ka beta' or one can simply call cousin.
Your mom's elder sister is your aunt; the son of your aunt is your cousin, and the daughter of your cousin is your cousin once removed.
In Tamil, elder sister is called "அக்கா" (Akka).
akka .. for elder thangai for younger
Your brother's wife is your sister-in-law.
You would call your mother's sister an aunt.
I believe it is your cousin-twice-removed. Definitely your cousin-once-removed's daughter.
sister in law
noona for elder sister 누나- that is how you right it
While generally referred to as a Sister-in-law, there is no relationship.
Sister-in-Law